摘要
2008年1月25～28日一次远离地面准静止锋的锋后暴雪突破了武汉百年气象史的多项纪录。利用NCEP再分析资料、MICAPS常规观测资料和FY-2CTBB资料诊断分析了这次暴雪过程。结果表明,这次暴雪与华南准静止锋关系密切,锋生、锋消变化与降雪天气的出现和停止一致;锋生函数各项在不同时段对锋生、锋消的贡献不同;水平变形项表现在总变形向量E上,水平辐散项表现在水平辐散场上,在锋生显著时期,伸长变形场与散度场大值带都与锋区重合。高低空急流的加速和有效配置诱发了急流—锋面次级环流产生,其对锋生、锋消变化具有一定的平衡作用,同时也与暴雪的出现和停止相关:反环流上升支不仅为暴雪天气提供了有利的动力条件,而且"逗点状"水汽输送也起了重要作用;正环流的出现使武汉上空出现下沉运动,水汽大幅度减少,暴雪天气相应停止。武汉的持续上升运动是在高低空急流有效配置、锋面的强迫抬升、急流—锋面次级环流的上升支,以及局地斜压大气力管环流上升支的支持、对称不稳定和位势不稳定层结综合作用下维持和发展的。
The weather situation,frontogenesis function and jet-front secondary circulation of Wuhan during the snowstorm process on 25~28 January 2008 are analyzed.The results show that the snowstorm happened with a condition of favorable atmospheric circulation and physical quantity.The change of frontogenesis function is consistent with the occurrence and stop of snowstorm.The elongation deformation in horizontal deformation term is the main reason for frontogenesis,while elongation deformation and shear deformation are both important to frontolysis.The horizontal convergence term has obvious effect on frontogenesis.The strengthening and effective allocation of upper and lower level jets make the jet-front secondary circulation occurring,which could balance frontogenesis and frontolysis.Meanwhile,the ascending branch of the jet-front secondary circulation transports the moisture upward and has a direct relation with the snowstorm in Wuhan.The upward motion in Wuhan is in the effective allocation of upper and low level jets,ascending branch of the jet-front secondary circulation,the front elevation,the solenoid in baroclinic atmosphere and the symmetric unstable and potential unstable stratification layer to maintain and develop.
出处
《高原气象》
CSCD
北大核心
2011年第6期1505-1515,共11页
Plateau Meteorology
基金
财政部/科技部公益性行业(气象)科研专项(GYHY200806007
GYHY201006014)
国家自然科学基金项目(40875022
41075048)共同资助
关键词
暴雪
锋生函数
急流—锋面次级环流
Snowstorm
Frontogenesis function
Jet-front secondary circulation
